Ceropegia fusca

CC license photo by Rhiannon

If you like weird plants (and I do) then this one has to be one of the most peculiar you'll see on the fieldtrip. It seems to prefer growing in the shelter of larger plants in the middle band of our walk - you won't find it near the sea or in the disturbed higher area. It's so strange looking that I think sometimes people miss it because they don't realise what it is - their eyes pass over it as something dead.

It's not green and it's generally leafless - the plant is a strange collection of segmented cylindrical succulent stems which are coated in a silvery white wax. The colour of the latter ('glaucous') presumably deflects some of the harsh solar radiation in this environment. One can only assume enough light gets through to some chlorophyll beneath to enable the plant to photosynthesise. The wax presumably also prevents moisture loss. Some Ceropegia species do seem to use Crassulacean Acid Metabolism (an adaptation where the non-light-using parts of photosynthesis are done at night, when the stomata can be opened without too much water loss) and perhaps this one does too.

CC license photo by Rhiannon

Here at the growing tip the stem does look a little greener.  Those two thin horn-like structures are indeed leaves (but often they don't last long).

CC license photo by Rhiannon

I was lucky enough to spot some of the very strange flowers. According to the Ceropegia Blog  (which contains more than you ever realised there was to know about Ceropegias) the flowers of this group are pollinated by flies. Some species have nice smelling flowers, others attract their flies using more revolting smells. If you spot some flowers perhaps you could give them a sniff and report back. The smells are said to mimic those of the flies' food sources or the places they prefer to lay eggs
(those could be some pretty stinky places). It seems that in some instances the scent holds a very twisted story.

 This article by Heiduk et al. (2017) explains some of the secrets of the flowers. Across the Ceropegias they share a basic structure. You can see the five petals fused at the top to give five entrances for visiting flies, and this is where the alluring scent is produced. Below, the fused petals form a long tube which is slippery or hairy inside, so flies falling in find it difficult to escape. The flower now has the insects where it wants them, alongside the pollen-producing and pollen-accepting parts of its anatomy. Ceropegias are apparently able to imprison their visitors for several hours, ensuring pollination! They don't offer any food or nectar, so essentially the flies are being attracted in by deceit.

You might also want to observe whether there are any spiders or any other predators lurking around the flowers - if flies are being lured in, then perhaps it would be a fruitful place to wait for them.


This paper mentions that the plant has been traditionally used on Tenerife as a cicatrizant (to promote wound healing) and as a disinfectant: experiments did show that extracts from it had some antibacterial activity.